A Scanning Electron Microscopic Study of Oviduct Epithelium in Culling Repeat Breeder Gilts

In the porcine reproductive tract, the oviduct is the vital organ for fertilization and early embryonic development. Repeat breeder (RB) gilts have previously shown the abnormal histological changes and deviant hormonal levels throughout estrous cycle. The aim of present study was to examine the oviduct epithelium of gilts culled due to RB (n = 9) in comparison to normal sows (controls, n = 6) by scanning electron microscope (SEM). The reproductive organs were collected after sending the RB gilts to local abattoir and their ovaries were kept to classify the estrous cycle. The ultrastructural details of control oviduct epithelium composed of ampulla, isthmus and uterotubal junction (UTJ) at follicular (n = 3) and luteal (n = 3) phases were similar to earlier studies. The surface of lining epithelium differed in appearance between controls and RB gilts. In all segments of gilt oviducts, the cilia were fused together with mucous-like substance and disarrangement; microvilli were sparse and almost disappeared. The epithelial surface was obviously covered with mucous-like debris and inflammatory cells. In the ampulla, the secretory cells were smaller and less cytoplasmic protrusions including sloughing of epithelial cells. The findings indicate that the abnormal ultrastructure presented in the RB gilts affected the oviductal environment and function resulting in failure of gamete transports, fertilization and early embryonic development.